Temperature-dependent color-tunable persistent luminescence in Ba0.95Sr0.05Ga2-yGdyO4:Bi3+ phosphor for advanced anti-counterfeiting

As emerging anti-counterfeiting materials, persistent luminescence (PersL) materials have attracted much attention owing to their particular luminescent properties, including durable luminescence, facile identification, high security and environment-friendly. Especially, exploiting color-tunable dynamic afterglow materials that facilitate the use of advanced technology such as multi-mode dynamic anti-counterfeiting remains of great realistic significance. Herein, a series of Ba 0.95 Sr 0.05 Ga 2- y Gd y O 4 :Bi 3+ phosphors with tunable photoluminescence and PersL were synthesized by the cationic substitution strategy. The displacement of Ga 3+ by Gd 3+ induces an additional blue emission owing to the generation of a new Bi 3+ luminescence center. The pure white light is realized in Ba 0.942 Sr 0.05 Ga 1.9 Gd 0.1 O 4 :0.8 %Bi 3+ ,0.25 %K + when excited by 325 nm light. Besides, color-tunable emission is triggered by changing the excitation wavelength or temperature. Significantly, excellent room-temperature PersL and dramatically intensified PersL with tunable color output under thermal stimulation are clearly discernible. Such properties result from the existence of multiple Bi 3+ luminescent centers and traps. These findings open up new ideas to produce color-tunable dynamic PersL materials for advanced anti-counterfeiting, information storage and encryption.